Coating for protecting ebc and cmc layers and thermal spray coating method thereof

Abstract

A multi-layer coating arrangement includes an environmental barrier coating (EBC) over a substrate; and at least one dense vertically cracked (DVC) coating layer over the EBC. The at least one DVC layer is resistant to erosion, water vapor corrosion and to calcium-magnesium-aluminum-silicate (CMAS).

1 . A multi-layer coating arrangement comprising:
 an environmental barrier coating (EBC) over a substrate; and   at least one dense vertically cracked (DVC) coating layer over the EBC, the at least one DVC layer being resistant to at least one of erosion, water vapor corrosion, and calcium-magnesium-aluminum-silicate (CMAS).   
     
     
         2 . The coating of  claim 1 , wherein the at least one DVC layer is a top layer. 
     
     
         3 . The coating of  claim 1 , further comprising at least one bond coating layer between the EBC and the substrate. 
     
     
         4 . The coating of  claim 1 , wherein the substrate comprises a ceramic matrix composite (CMC). 
     
     
         5 . The coating of  claim 1 , wherein the at least one DVC coating layer comprises RE-stabilized ZrO 2  or RE-stabilized HfO 2 . 
     
     
         6 . The coating of  claim 1 , wherein the at least one DVC coating layer comprises RE-stabilized ZrO 2  mixed with a rare earth oxide, or comprises RE-stabilized HfO 2  mixed with a rare earth oxide. 
     
     
         7 . The coating of  claim 1 , wherein the at least one DVC coating layer comprises RE-stabilized ZrO 2  mixed with a rare earth silicate, or comprises RE-stabilized HfO 2  mixed with a rare earth silicate. 
     
     
         8 . The coating of  claim 1 , wherein the at least one DVC coating layer comprises RE-stabilized ZrO 2  mixed with a rare earth aluminate, or comprises RE-stabilized HfO 2  mixed with a rare earth aluminate. 
     
     
         9 . The coating of  claim 1 , wherein the at least one DVC coating layer comprises RE-stabilized ZrO 2  mixed with a rare earth aluminate or silicate, or comprises RE-stabilized HfO 2  mixed with a rare earth aluminate or silicate. 
     
     
         10 . The coating of  claim 1 , wherein the at least one DVC coating layer comprises RE-stabilized ZrO 2  mixed with an alkaline oxide, or comprises RE-stabilized HfO 2  mixed with an alkaline oxide. 
     
     
         11 . The coating of  claim 1 , wherein the at least one DVC coating layer comprises RE-stabilized ZrO 2  mixed with a gadolinium zirconate, or comprises RE-stabilized HfO 2  mixed with a gadolinium zirconate. 
     
     
         12 . The coating of  claim 1 , wherein the at least one DVC coating layer comprises rare earth silicates. 
     
     
         13 . The coating of  claim 1 , wherein the at least one DVC coating layer comprises a mixture of two or more of:
 RE-stabilized ZrO 2  or RE-stabilized HfO 2 ;   RE-stabilized ZrO 2  mixed with a rare earth oxide, or RE-stabilized HfO 2  mixed with a rare earth oxide;   RE-stabilized ZrO 2  mixed with a rare earth silicate, or RE-stabilized HfO 2  mixed with a rare earth silicate;   RE-stabilized ZrO 2  mixed with a rare earth aluminate, or RE-stabilized HfO 2  mixed with a rare earth aluminate;   RE-stabilized ZrO 2  mixed with a rare earth aluminate or silicate, or RE-stabilized HfO 2  mixed with a rare earth aluminate or silicate;   RE-stabilized ZrO 2  mixed with an alkaline oxide, or RE-stabilized HfO 2  mixed with an alkaline oxide;   RE-stabilized ZrO 2  mixed with a gadolinium zirconate, or RE-stabilized HfO 2  mixed with a gadolinium zirconate; and   Rare earth silicates.   
     
     
         14 . The coating of  claim 1 , wherein the at least one DVC coating layer comprises full thickness vertical cracks. 
     
     
         15 .- 26 . (canceled) 
     
     
         27 . A method of forming a coating that is resistant to erosion, water vapor corrosion and to CMAS on a substrate coated with at least one EBC coating layer, the method comprising:
 plasma spraying a DVC coating material over the at least one EBC coating layer.   
     
     
         28 . The method of  claim 27 , wherein the coating further comprises at least one bond coating layer between the at least one EBC coating layer and the substrate. 
     
     
         29 . The method of  claim 27 , wherein the plasma spraying comprises one of:
 atmospheric plasma spraying (APS);   physical vapor deposition (PS-PVD); and   suspension plasma spray (SPS).   
     
     
         30 .- 31 . (canceled) 
     
     
         32 . The coating of  claim 1 , wherein no CTE-mitigating layer is present between the DVC layer and the EBC. 
     
     
         33 . The coating of  claim 1 , wherein no porous vertically cracked (PVC) intermediate layer is present between the DVC layer and the EBC.